FIG. 2.

Longitudinal nitrite production to mycobacterial antigens. Blood mononuclear cells were isolated from control (n = 10), M. kansasii-infected (n = 4), and M. bovis-infected (n = 9) cattle at the indicated time points after challenge. Isolates were cultured for 72 h with medium alone, 1 μg/ml rESAT-6-CFP-10, or 5 μg/ml PPDs, and supernatants were harvested for analysis of nitrite (Griess reaction) as an indication of NO production. Values are presented as mean (±standard error) responses to rESAT-6-CFP-10 (A) or M. bovis PPD (B) stimulation minus the response to medium alone. The letters a to c indicate responses that differ (P < 0.05) for each respective time point after challenge.